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Nesting Colonies (nesting + colony)
Selected AbstractsHigh prevalence of antimicrobial-resistant genes and integrons in Escherichia coli isolates from Black-headed Gulls in the Czech RepublicJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2007M. Dolejska Abstract Aims:, To carry out an assessment of the occurrence of resistance to antimicrobials in Escherichia coli that has been isolated from young Black-headed Gulls in three nesting colonies. Methods and Results:, A total of 257 isolates were tested for sensitivity to eight antibacterial substances by disk diffusion method. The polymerase chain reaction was used for detecting specific genes of antibacterial resistance and class 1 integrons in resistant E. coli isolates. A total 75 (29·9%) of 257 isolates were resistant to one or more antimicrobial agents. The dominant type of resistance was to tetracycline, detected in 49 (19·1%) isolates. Resistance to ampicillin was detected in 30 (11·7%), cephalothin in 11 (4·3%), streptomycin in 24 (9·3%), sulphonamides in 20 (7·8%) and chloramphenicol in 5 (1·9%) isolates. Nine isolates carrying integrons were detected. Conclusions:, The study suggests that young Black-headed Gulls are an important host reservoir of resistant E. coli strains, probably reflecting the presence of such strains in their sources of food and/or water. Significance and Impact of the Study:, Although Black-headed Gulls do not naturally come into contact with antibiotics, these birds can be infected with resistant E. coli and potentially serve as their reservoirs, vectors and bioindicators in the environment. [source] Conservation implications of complex population structure: lessons from the loggerhead turtle (Caretta caretta)MOLECULAR ECOLOGY, Issue 8 2005B. W. BOWEN Abstract Complex population structure can result from either sex-biased gene flow or population overlap during migrations. Loggerhead turtles (Caretta caretta) have both traits, providing an instructive case history for wildlife management. Based on surveys of maternally inherited mtDNA, pelagic post-hatchlings show no population structure across the northern Atlantic (,ST < 0.001, P = 0.919), subadults in coastal habitat show low structure among locations (,ST = 0.01, P < 0.005), and nesting colonies along the southeastern coast of the United States have strong structure (,ST = 0.42, P < 0.001). Thus the level of population structure increases through progressive life history stages. In contrast, a survey of biparentally inherited microsatellite DNA shows no significant population structure: RST < 0.001; FST = 0.002 (P > 0.05) across the same nesting colonies. These results indicate that loggerhead females home faithfully to their natal nesting colony, but males provide an avenue of gene flow between regional nesting colonies, probably via opportunistic mating in migratory corridors. As a result, all breeding populations in the southeastern United States have similar levels of microsatellite diversity (HE = 0.70,0.89), whereas mtDNA haplotype diversity varies dramatically (h = 0.00,0.66). Under a conventional interpretation of the nuclear DNA data, the entire southeastern United States would be regarded as a single management unit, yet the mtDNA data indicate multiple isolated populations. This complex population structure mandates a different management strategy at each life stage. Perturbations to pelagic juveniles will have a diffuse impact on Atlantic nesting colonies, mortality of subadults will have a more focused impact on nearby breeding populations, and disturbances to adults will have pinpoint impact on corresponding breeding populations. These findings demonstrate that surveys of multiple life stages are desirable to resolve management units in migratory marine species. [source] Natal homing in juvenile loggerhead turtles (Caretta caretta)MOLECULAR ECOLOGY, Issue 12 2004BRIAN W. BOWEN Abstract Juvenile loggerhead turtles (Caretta caretta) from West Atlantic nesting beaches occupy oceanic (pelagic) habitats in the eastern Atlantic and Mediterranean, whereas larger juvenile turtles occupy shallow (neritic) habitats along the continental coastline of North America. Hence the switch from oceanic to neritic stage can involve a trans-oceanic migration. Several researchers have suggested that at the end of the oceanic phase, juveniles are homing to feeding habitats in the vicinity of their natal rookery. To test the hypothesis of juvenile homing behaviour, we surveyed 10 juvenile feeding zones across the eastern USA with mitochondrial DNA control region sequences (N = 1437) and compared these samples to potential source (nesting) populations in the Atlantic Ocean and Mediterranean Sea (N = 465). The results indicated a shallow, but significant, population structure of neritic juveniles (,ST = 0.0088, P = 0.016), and haplotype frequency differences were significantly correlated between coastal feeding populations and adjacent nesting populations (Mantel test R2 = 0.52, P = 0.001). Mixed stock analyses (using a Bayesian algorithm) indicated that juveniles occurred at elevated frequency in the vicinity of their natal rookery. Hence, all lines of evidence supported the hypothesis of juvenile homing in loggerhead turtles. While not as precise as the homing of breeding adults, this behaviour nonetheless places juvenile turtles in the vicinity of their natal nesting colonies. Some of the coastal hazards that affect declining nesting populations may also affect the next generation of turtles feeding in nearby habitats. [source] Experimental Study of Nest-site Selection in the Biscutate Swift (Streptoprocne biscutata, Aves: Apodidae) in Southern BrazilBIOTROPICA, Issue 1 2009Mauro Pichorim ABSTRACT Biscutate swift Streptoprocne biscutata nests are usually built on protected rocky cliff walls. Birds often renest at the same location. Remains of previous nests may offer information about potential nests and quality of nest-sites. Here, we experimentally study nest-site selection to test the hypothesis that information from previous nests is used in current nest-site selection. We placed old nest material at artificial nest-sites to test whether new nest-sites are chosen based on the presence of nesting material. We also tested whether the use of natural nest-sites is influenced by nesting material by creating two types of natural sites: previously used natural nest-sites with vestiges of old nests removed and never used natural nest-sites to which vestiges of old nests were added. In the first experiment, in 139 nest-use opportunities, 16 artificial nest-sites were used, all of which included vestiges. In the second experiment, in 91 nest-use opportunities, four nests were in previously unused but natural locations to which vestiges had been added, 22 nests were in previously used sites without vestiges, and the remaining 65 nests remained unused. Two processes are apparently in action: first, prior experience and memory; second, vestiges indicate where nesting has occurred, possibly useful for first breeding, or for imperfect memory. Previous nesting information may explain why swifts use nesting locations for many years and why new nesting colonies seldom form. This transmission of information suggests that swifts tend to be conservative and nest where previous nesting has occurred. RESUMO Streptoprocne biscutata nidifica em locais protegidos em grandes paredes rochosas, os casais geralmente usam o mesmo local de nidificação ao longo de vários anos. Restos de nidificações prévias podem fornecer informações sobre a qualidade do sítio de nidificação. No presente trabalho, testamos, experimentalmente, a hipótese de que estas aves usam evidências de nidificações prévias para a escolha de um local para a construção do ninho. Para isso, nós instalamos substratos artificiais de nidificação com e sem ninhos de estações reprodutivas anteriores para testar se novos locais de reprodução são escolhidos em função da presença de material nidular. Nós também testamos se o uso de sítios naturais é influenciado pela presença de material nidular por meio de dois tratamentos: sítios naturais previamente usados, mas com todos os vestígios de ninhos velhos removidos e sítios naturais nunca usados adicionados de vestígios de ninhos velhos. No primeiro experimento, de 139 oportunidades de nidificação apenas 16 substratos artificiais foram usados. Entretanto, todos os substratos utilizados possuíam vestígios de nidificações passadas. No segundo experimento, em 91 oportunidades de nidificação quarto ninhos foram construídos em sítios naturais nunca usados aos quais foram adicionados materiais, 22 ninhos foram construídos em sítios previamente usados, mas desprovidos de materiais e os 65 sítios restantes permaneceram sem uso. Com base nos dados obtidos concluímos que, aparentemente, dois processos estão agindo: a experiência anterior e a memória parecem atuar em primeiro lugar, em segundo lugar os vestígios de ninhos funcionam, possivelmente, como um indicativo da qualidade do local para aves que estão nidificando pela primeira vez ou pra os casos de memória imperfeita. Informações sobre nidificações prévias podem explicar porque andorinhões usam os mesmos sítios de reprodução por muitos anos e porque raramente novas colônias reprodutivas são estabelecidas. Esta transmissão de informação sugere que os andorinhões tendem a ser conservativos, nidificando em locais previamente usados para reprodução. [source] Conservation implications of complex population structure: lessons from the loggerhead turtle (Caretta caretta)MOLECULAR ECOLOGY, Issue 8 2005B. W. BOWEN Abstract Complex population structure can result from either sex-biased gene flow or population overlap during migrations. Loggerhead turtles (Caretta caretta) have both traits, providing an instructive case history for wildlife management. Based on surveys of maternally inherited mtDNA, pelagic post-hatchlings show no population structure across the northern Atlantic (,ST < 0.001, P = 0.919), subadults in coastal habitat show low structure among locations (,ST = 0.01, P < 0.005), and nesting colonies along the southeastern coast of the United States have strong structure (,ST = 0.42, P < 0.001). Thus the level of population structure increases through progressive life history stages. In contrast, a survey of biparentally inherited microsatellite DNA shows no significant population structure: RST < 0.001; FST = 0.002 (P > 0.05) across the same nesting colonies. These results indicate that loggerhead females home faithfully to their natal nesting colony, but males provide an avenue of gene flow between regional nesting colonies, probably via opportunistic mating in migratory corridors. As a result, all breeding populations in the southeastern United States have similar levels of microsatellite diversity (HE = 0.70,0.89), whereas mtDNA haplotype diversity varies dramatically (h = 0.00,0.66). Under a conventional interpretation of the nuclear DNA data, the entire southeastern United States would be regarded as a single management unit, yet the mtDNA data indicate multiple isolated populations. This complex population structure mandates a different management strategy at each life stage. Perturbations to pelagic juveniles will have a diffuse impact on Atlantic nesting colonies, mortality of subadults will have a more focused impact on nearby breeding populations, and disturbances to adults will have pinpoint impact on corresponding breeding populations. These findings demonstrate that surveys of multiple life stages are desirable to resolve management units in migratory marine species. [source] | ||||||||||